Chair frame



FIG. 1 is a perspective view of a chair frame embodying my new design;

FIG. 2 is a front elevation view thereof;

FIG. 3 is a right side elevation view thereof, the left side elevation being the mirror image thereof;

FIG. 4 is a rear elevation view thereof; and,

FIG. 5 is a top plan view thereof.

The broken lines depicting the seat have been shown for illustrative purposes only and form no part of the claimed design. 

The ornamental design for a chair frame, as shown and described. 